MINNEAPOLIS — Buying ahead of rapid food-cost inflation and taking advantage of an early Easter holiday, Nash Finch boosted inventories and profits during the first quarter, which ended March 22. Net profits of $11.3 million, or 85 cents a share, improved 113.2% on sales of $1.02 billion. Sales fell by 1% overall but improved by 1.7% excluding effects of the departure of a large wholesale customer and an Easter holiday that fell in the first quarter this year but the second quarter in fiscal 2007. Food-cost inflation — which Alec Covington, Nash Finch’s chief executive officer, described as highest since the 1970s — helped sales as Nash Finch ramped up inventory ahead of the increases and passed the savings along to customers, Covington said. EBITDA of $30.6 million improved by 20% excluding one-time items, the company said. Nash Finch stock was up by more than 9% Thursday.